1. Field of the Invention
This invention relates to polymer and shaped aramid and polybenzimidazole articles which exhibit an inherent water repellency and to a process for making such inherently water repellent aramid and polybenzimidazole articles. The articles include fibers; and the process for increasing the water repellency of the articles includes a reaction wherein fluoroalkyl groups are grafted onto the surface of the polymer.
2. Description of the Prior Art
Japanese Publication (Kokai) No. 62-81426, published Apr. 14, 1987 on the application of Asahi, discloses a process for treating aramid surfaces to render them more hydrophobic and decrease the coefficient of moisture absorption. The process includes: contact of the aramid surface by alkali metal hydrocarbyls or alkaline earth metal hydrocarbyls in no solvent or in a solvent specifically required to be less polar than dimethyl sulfoxide; and then contact of the metallated aramid by a halogenated aliphatic compound in no solvent or in a solvent specifically required to be less polar than dimethyl sulfoxide. There is no mention of the use of fluoroalkyl-containing alkylating agents.
Japanese Patent No. Sho 62-91542, published Apr. 27, 1987 on the application of Asahi, discloses a process for treating aramid surfaces to render them more hydrophilic and increase the coefficient of moisture absorption. The process includes: contact of the aramid surface by alkali metal-containing or alkaline earth metal-containing compounds in a solvent specifically required to be at least as polar as dimethyl sulfoxide; and then, reacting the aramid surface with water or other polar compound.
Japanese Publication (Kokai) No. 62-110,968, published May 22, 1987, discloses grafting materials to aramid fibers, through the use of epoxide-functional grafting agents, to create a surface with reactive epoxide groups.